The aims of this project are to evaluate virulence and immune response of selected human and animal rotaviruses in experimentally infected animals, and to study cross-protection between selected strains of human and animal rotaviruses. Study of potential vaccine strains in experimental animals also constitutes an additional test for the presence of adventitious agents. Experimental animal systems that are currently available and that have been shown to be suitable for the study of rotavirus infection and in some cases disease, are the colostrum-deprived newborn rhesus monkey and the gnotobiotic piglet. Chimpanzees, rhesus monkeys and African green monkeys are also utilized to examine the safety of potential rotavirus vaccine preparations. Piglets were delivered by Caesarean section and maintained in plastic isolators under gnotobiotic conditions; monkeys were maintained under strict isolation in contained units. Sera and fecal samples derived from the animal studies were analyzed for antibody and antigen by a variety of laboratory techniques. Enzyme immunoassay was used to evaluate fecal samples for antigen, while complement fixation, immune adherence hemagglutination assay and/or plaque reduction neutralization assay were used to evaluate sera and fecal samples for antibody response.